Kettle furnace



Feb. 1, 1949;

o. R. OLSQN KETTLE FURNACE Patented Feb. 1, 1949 UNITED STATES PATENT OFFICE &460392 KETTLE FURNACE Oscar E. Olsen, Pittsburgh, Pa. Application March 22, 1946, Serial No. 656319 10 Claims. (CI. 263- 11) This invention relates generally to improvements in kettle urnaces and more particularly to improvements in the method of building and in the construction of kettle furnaces to contain a heated liquid bath in which articles are immersed for heat treatment or coating.

Kettle furnaces of this character may contain salt solutions such as a Houghton salt solution that will not evaporate at elevated temperatures, or contain baths containing lead, tin or Zinc, the latter of which is employed as a spelter for galvanizing the surface of the articles immersed. The salt and lead baths are employed to uniformly heat the articles for annealing or normalizing treatment.

The principal object of this invention isa novel kettle iurnace Construction that provides a uniform deterioration of the -kettle walls, thereby prolonging the life of the kettle.

Another object is the provision of a kettle or tank furnace that is more eflicient and operates with a materially less fuel input per unit tonnage of articles treated.

Another object is the provision of a sump for Conveniently recovering the bath without destruction of the furnace in case the kettle bursts.

Another object is the Construction of a bathrecovering sump and drain which may function without foul'ng the fiues and do not afiect the operation of the latter.

Another object is the provision of a novel construction and method of assembling the combustion chamber and fiues in a kettle furnace.

Another object is the provision of novel tile Construction blocks for fabricating the combustion chamber and fiues of a kettle furnace.

Other objects and advantages appear in the following description and claims wherein:

Fig. 1 is a view in horizontal section of the furnace comprising this invention taken along the line l-l of Fig. 2.

Fig. 2 is a View in Vertical section taken along the line 2-2 of Fig. 1.

Fig. 3 is an enlarged isometric View showing a portion of the tile for the construction of the urnace.

Fig. 4 is an enlarged View of a series of arched outlet ports disassociated from the furnace structure.

Fig. 5 is a sectional View of a kettle urnace having a double-decker burner in each side Wall.

Fi'g. 6 is a perspective View illustrating the inverted pier arches which form the downtake outlets to the flues.

Referrin'g to the drawings the furnace is built within the pit i which is lined with a reinforced concrete consisting of the bottom mat 2 which extends the full length of the pit and the vertical walls 3. A moat i with sloping side walls isformed in the bottom of the pit along each side of the mat 2 or the full length of the pit. The .buckstays 5 are anchored by embedding their lower ende in the concrete. These buckstays preferably extend upwardly above the top of the pit. A* concretepartition 6 encases a portion of the outer side of each buckstay and ex-V tends across the moats 4 and connects with the side walls 3 to brace the buckstay and to divide the moats into independent compartments which are interconnected by the weirs 'i in the top of each partition E. The side surfaces of these partition walls are also provided with a batter.

A thick insulating firebrick base ,8 is laid on the top of the mat 2 and extends between the buckstays 5 which surround the central portion of the mat 2. At the location of each burner, of which there are three between adjacent buckstays, the base 3 is formed with an outwardly and, downwardly sloping trough 9. Three oi i these lateral troughs 9 open into one of the compartments in the moats 4.

The kettle li! is a fabricated steel open top tank with smooth welded joints and capable of holding a liquid and withstanding high temperatures. pit. The aggregate Capacity of the compartments of the moat 4 preferably equals the capacity of the tank I!) to enable the moat to receive the whole of the contents in case the tank bursts.

The top of the frebrick base 8 is conditioned to receive and fully support the tank ill. The combustion chambers and fiues are constructed around the tan A barrier wall H oi frebrick tile is first laid on the base 8 surrounding the lower portion of the tank. The barrier wall and the base thus completely encase the lower portion ofthe tanl i@ in insulating material and no openings or ilues are extended through or The top third portion of the barrier two-thirds of this wall is oi uniiorm thickness. This Construction of the barrier wall is important as it permitsproper heating of the tank bottom through the barrier.

The space between adjacent buckstays 5 is divided into a, plurality of compartments, such as three compartments of equal dimension, to provide the independent combustion chambers !2. A lateral firebrick tile pier !3 is constructed on The walls of the tank extend above the` E? indicates the horizontal tile slabs which form the top wall of the their enter wall i@ and their inner portions resting on ..top of the arched outlet walls fiues are laid with' `on the center Iines of the slabs i? form a continnous iS and a fioor for the fire beds !8.

A contnuous bridge wall I &made of firebrick tile is laid along the slabs i? adjacent their inner edges, therehy forming a continuous trough and segregating the fire bed !8 from the outer walls of the tani: .it and exposing the latter for the piers !3. Thus the wall shown at Zt is laid continuously along the top of the slabs i? adjacent their outer edges to form a continuation of the outer wall'i i. tile sections forming'the walls 20 have ports ZI therethrough to receive the burners 22.' burner is constructed to receive'the combustible tinuously to each' other in the same manner :as the -fiues 56. The upper portionofthe-bridge walls !3, which face the tank w; are-'made to through the 1 pointed as shown at 25 in Figa 3 tofacilitate the flow of the gases to the flues.

At each huckstay Sa partition wall zs extends from the outermost firebrick wall 2? to the tank i@ to shore thewall of the tank from the level' bers t for each burner, of which there are three between adjacent `side buckstays. The partitions 3% also extend'to the outermo'st wall 27: Thus the partition walls 'andstainterrupt theniebrick tile wah 35 which formsan' uDwardcontinuation of the wall-` sections i i "and 29.

The 'root slabs 23 extend over and rest on the tops of the wails 27 and 3! and bracing angle iron-empioyed to lock'the outer edges of the slabs 28 in alignment within the encirciing buckstays.

A grating 35 may' be supported between the pit wall 3 and the buckstays to'prevent ac i5 and' on the piers` 43 with the joints of adjacent'slabs !1 abutting ceiling for the fiues portions supported on the topzofjthe dents due to the open moats 4 and to provide access to the open tank li).

Outwardly 'opening cast iron fiap doors 36, hinged at the top, close the troughs 9 that run out under the outermost Walls 27 to prevent leakage of air into the fiues !6. i

A chain 31 is hooked on the wall 3 and permitted to iie in the bottom of each compartment of the moats 4. Thus if the tani: were to burst When containing lead, zincor tin; the metal will the barrie'r Wall H into the trough or troughs 9 and out through the ap doors 36 into the compartments of one or both moats d. When one moat compartment fills it is permitted to flow to adjacent compartments through i the weirs 'i' which are subsequently broken after solidication and the siabs of metal are raised by means of the chains 37 and the outrebuildingthe furnace. i

The-Enes ?G on each side of the furnace connect withan extension fiue 38'which is connected to the stack 35.

The :longitudnally disposed arched outiets. 55 as shcWn inFigs. 'z-and 3 form` an 'important part The manner in which said arch cutiets-are constructedisasfollows: An arch tile membersuch as shown ats in Fig. 4 which when built :into the-furnace under-:the s'labs i? may be iaidzdirectiy on the base &With the tile filier members ,2, 43 and 34 iaid on top'thereof to com ;oleteiy fill in the gap between the tiie %kand the siah' ii; Assumingthat the urnace is provided with ififteen burners on each: side thereof, the first'threeburner'sections adjacent the stack 39 would be iaid. inthi's manner to restrict the .flow of gasesat this end ;of `thefurnace and 'prevent the cfianes from short-circuiting longitudinally of'the downtake 243. Thenext: three burners would then have the short' or ieg tiles* iplaced cna thebase- 8 and the arched tile 36 cemented theieon andoniy the long tiles ii, z `and 33 wouidhe requiredton topthereoto fil] in'the gop.

'The thirdsseries of 'three .burnersections -woul d then: have 'two shortor leg tile sections and 453 withc oniy twofillertiiesii 'and t on* top' of the arched tile 28. The fourth'series has threeshort rorriegrzt'les 35; %rand i? and one longfiiler tile ii 'on top; whereas the fifth or last series of three burne'."sections, whichare remote of the stack, have'oniy the shortor leg tiles 145,' t 42' and 48 andsno fiiler tilesonthe topof the arched tile 46. In this manner'the restricted'onti'ets` i'' from the combusti'onchambers'iz :to the flues it' are graduatedtowproduce auniform pressure distribution. throughout the combustion chambers, thereby :providing a uniform distribution z of the burning gases even though the. fire beds ae ?and the downtakes Mare open to each otherforthe full length of the furnace.

With this construction substantialiy half .of the Walls of. the tanlhie adj'acent the com'bustionchambers 52 is exposed to the burning gases and thefuei .is provided `'to zsnpply a maximum of .Bi t. 'ufis' per'square foot exposed'per hour. This fuel Consumption rate will maintain a lead hat; at'l600 F; Th'e firingrateis reduced forthe dierent'charactersof bathe. Thus a Houghton salt bath' is maintained at 900 F., a .Zinc bath at 850 E and a tin bath at 600 F. The temper ature of the bath is measured by thermocycles which" are 'usedfor :regulating the fuehinput 'by systems commonly known in the furnace heating art. I`he fire beds '18 and the downtakes 2 3 'being directly connected provide an`even distribution of the heat on the tank and prevent the formation of localized hot spots which ordinarily cause tanks oi this character to become burned and rupture prematurely.

The double-deoker burner arrangement shown in Fig. 5 is constructed in the same manner as V the furnace with a single row of burners on each 'side as shown in Figs. 1 and 2. However the piers !3 and outlet arches &5 are replaced by the in verted arch members l. Each inverted arch member comprises the upwardly'projecting legs 5! and 52 which produce the opening or orifice 53 therebetween. When inverted as shown the 'bridge'portion 54 of the arch slopes from the barrier wall i I as shown at 55 to convey the bath from a bursted tank to the open trough '9. The

inverted arch member 5& is preferably made of tile and it is as long 'as the distance between the centers of the burners to enable the legs of adja- 'cent tile to replace the pierl3. Where the tile slabs H meet at the center line of the piers !3 in the structure of Figs. 1 to 3, in Fig. 5 the legs 51 and 52 support their respective slab H. v i

The openings 53 of the inverted arch members 56 become increasingly larger as they progress from the stack end of the fiue !6 to produce an even draft on the downtake and prevent the burning fuel from takng a short-circuiting path.

beds !8. The bridge wall 50 is supported by the slabs 51 and' in turn supports the lateral combustion chamber partitions Bl with the aid of the furnace wall 52. The wall section 52 also supports the wall section 53 and all of these Wall sections are'tied in with the outer wall 21. The roof 28 is supported by the furnace side walls and the partitions e! and close the top of the combustion chambers 64.

The burning gases from the combustion Chamber 64 flow through the downtake in front of the bridge wall 651 and are reheated by the additional burning fuel from the combustion chamber [2 and they continue down the downtake and flow through the outlets 53 produced by the inverted arch members 59 to the fine as and thence to the end of the furna'ce and on to the stack. Proper damper means are provided to regulate the draft.

With this double-decker burner arrangement a much deeper tank n may be properly heated and the very bottom of the tani; is properly shielded from intense heat to prevent agitation of the precipitant in both structures.

I claim:

1. In a kettle furnace the combination of a mat having a flat continuous surface, an open top tank supported on the mat, furnace end walls covering the end of the tank, a relatively low barrier wall on the mat along each side of the tank for boxing in the bottom thereof, furnace side walls connectng the end walls and spaced outwardly from the barrier walls, a row of fuel burners in each urnace side wall, a series, of spaced piers extending laterally from each barrier wall but stopping short from their respective 'furnace side wallto provide a longitudinal flue space, a slab supported by the outer ends of the V piers and the furnace side wallsbelow the burners to form a ceiling for the flues and a fuel bed floor for the burners, an upwardly projecting bridge wall along the inneredge of the slabs and spaced from the tank to shield it from the fire beds and to provide a downtake to the outlets between the piers to the flues, and a 'roof supported above the bridge walls to provide' combus- 'tion chambers connecting the fire beds with the downtake. i 2. The structure of claim 1 which also includes spaced lateral partitions supported on the bridge -walls to partition ofi portions of the combustion chambers for each burner and aid in supporting the roofs. i

3 The structure of claim 1 which also includes spaced lateral partitions supported on the bridge walls to partition off'portions of the oombustion 'chainbers for each burner and aid in supporting said roofs, and characterized in that said piers 'are aligned With said partitions. i 4. The structure of claim 1 which also includes a V spaced lateral partitions supported on the bridge jwalls to partition ofi portions of the combustion chambers for each burner and aid in supporting said roofs, and 'characterized in that said piers are aligned 'with said parttons and 'certain of e said lateral partitions extendng from the wall of the tank to the furnace side wall.

5.' In a kettle furnace the combination of a mat having a flat continuous surface, an open top tank supported on the mat, furnace end walls covering the end of the tahi a relativelylow barrier wall on the mat along each side of the tank for boxing in the bottom thereofffurnace side walls connecting the end walls and spaced outwardly from the barrier walls, a row of fuel burners in each furnace side wall, a series of spaced piers extending laterally from each barrier Wall but stopping short from their respective furnace side wall to provide a longitudinal flue space, a slab supported by the outer ends of the piers and the furnace side walls below the burners to form a ceiling for the fiues and a fuel bed floor for the burners, an upwardly projecting bridge Wall along the inner edge of the slabs and spaced from the tank to shield it from the fire beds and to provide a downtake to the outlets between the piers to the flues, a roof supported above the bridge walls to provide combustion chambers connecting the fire beds with the downtake, a stack adjacent one end of the furnace, means connecting the ends of the iiues to said stack, and means between adjacent piers to restrict the outlets progressively toward the stack end of the furnace.

6. In a kettle furnace the oombination of a mat having a fiat continuous surface, an open top tank supported on the Inat, furnace end walls covering the end of the tank, a relatively low barrier wall on the mat along each side of the tank for boxing in the bottom thereof, furnace side walls connecting the end walls and spaced outwardly from the barrier walls, a, row of fuel burners in each furnace side wall, a series of spaced piers extendng laterally from each barrier wall but stopping short from their respective furnace side wall to provide a longitudinal flue space, a slab supported by the outer ends of the piers and the urnace side walls below the burners to form a ceiling for the lues and a fuel bed floor for the burners, an upwardly proiecting bridge wall along the inner edge of the slabs and spaced from the tani: to shield it from the ..ported above the 'the d'ownt'akea 'iurnace means connecting the ends of the fiues a slab supported by fire beds and to lets .between the provide a downtake to the outpiers to the fiues, a roof sup- ,bridge walls to provide combustion chambers connecting the fire beds With stack adjacent one end of the to said stack, and arch means between adjacent piers to restrict said outlets progressively toward the stack end of the furnace.

7. In a double-decker fired open top kettle furrrace the combination of a mat, an open top tank supported on the mat, furnace end walls supported on the mat and covering the ends of the tank and extending V therebeyond, furnace side walls supported en the mat and spaced from the sides of the tenk and connected to the end walls, parallel rows of spaced fuel burners in each furnace side wall, a plurality of laterally extending piers extending from the tank but spaced from the side walls toprovide a longitudinal flue space, the piers and the urnace side walls below the lowest row of burners 'but having its inner edge spaced from the tank, an upwardly projecting bridge Wall along the inner edge of the slabs to shield 'the tank from direct impin-gement of the take between the piers to the fiues, a second slab supported above said bridge walls and below the upper row of burners to form a combustion chamber ceiling for the lower burners but having its inner edge spaced from the tenk, another up- -wardlyprojecting bridge wall along the inner iedge of the second slabs to shield the tenk from` direct impingement of the flames and to extend the downtake ported above the furnace.

between the piers, and a roof supthe upper bridge walls to enclose flames and provide a doWn- 8. The structure of claim 7 which also includes spaced lateral partitions supported by the iurnace side walls and each of the bridge walls ,to partition off portions of the combustion chambers for each burner, the lower partitions supporting the upper slabs and the upper partitions supporting said roofs.

9. The structure of claim 7 characterized in that said piers are constructed from the legs of a-n inverted arch and .the passages produced thereby form the outlets of the downtakes to the fiues.

10.The structure of claim 7 characterized in that said piers are constructed from the legs of adjacent' invertedarches, the orifices of said arches being progressively larger from the discharge end of the fiue to the other end of the furnace.

- OSCAR R. OLSON.

e REFERENCES CITED The following references are of record in the file of this patent: i

UNITED STATES PATENTS OTHER REFERENCES "Industrial Furnaces, vol. I, by W. Trinks, third edition, 4th printing, January,r 1944, published by John Wiley &Sons Inc., NeW York, N. Y., page 386. 

